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cifs: destage dirty pages before re-reading them for cache=none

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commit bb44c31cdcac107344dd2fcc3bd0504a53575c51 upstream.

This is the opposite case of kernel bugzilla 216301.
If we mmap a file using cache=none and then proceed to update the mmapped
area these updates are not reflected in a later pread() of that part of the
file.
To fix this we must first destage any dirty pages in the range before
we allow the pread() to proceed.

Cc: stable@vger.kernel.org
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ronnie Sahlberg 2022-09-20 14:32:02 +10:00 committed by Greg Kroah-Hartman
parent 8298f20e11
commit bd09adde67
1 changed files with 9 additions and 0 deletions
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9
fs/cifs/file.c
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@ -3877,6 +3877,15 @@ static ssize_t __cifs_readv(
len = ctx->len;
}
if (direct) {
rc = filemap_write_and_wait_range(file->f_inode->i_mapping,
offset, offset + len - 1);
if (rc) {
kref_put(&ctx->refcount, cifs_aio_ctx_release);
return -EAGAIN;
}
}
/* grab a lock here due to read response handlers can access ctx */
mutex_lock(&ctx->aio_mutex);